Cationic ring-opening polymerizations of 2-oxazolines were investigated in continuous microflow reactors. Fast homopolymerizations of 2-ethyl-2-oxazoline (EtOx) and 2-n-propyl-2-oxazoline (nPropOx) were carried out up to 180 degrees C, yielding well-controlled polymers. Also well-defined diblock and triblock copolymers were produced in a microfluidic reactor cascade, demonstrating the high value of microflow synthesis for the built-up of advanced poly(2-oxazoline)-based polymers.